In preparation for the second patch, abstract away the THP allocation
logic present in the create_huge_pmd() path, which corresponds to the
faulting case when no page is present.
There should be no functional change as a result of applying this patch,
except that, as David notes at [1], a PMD-aligned address should
be passed to update_mmu_cache_pmd().
[1]: https://lore.kernel.org/all/ddd3fcd2-48b3-4170-bcaa-2fe66e093f43@redhat.com/
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Dev Jain <dev.jain@arm.com>
---
mm/huge_memory.c | 98 ++++++++++++++++++++++++++++--------------------
1 file changed, 57 insertions(+), 41 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4e34b7f89daf..bdbf67c18f6c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1148,47 +1148,81 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
}
EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
-static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
- struct page *page, gfp_t gfp)
+static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
+ unsigned long addr)
{
- struct vm_area_struct *vma = vmf->vma;
- struct folio *folio = page_folio(page);
- pgtable_t pgtable;
- unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
- vm_fault_t ret = 0;
+ unsigned long haddr = addr & HPAGE_PMD_MASK;
+ gfp_t gfp = vma_thp_gfp_mask(vma);
+ const int order = HPAGE_PMD_ORDER;
+ struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true);
- VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
+ if (unlikely(!folio)) {
+ count_vm_event(THP_FAULT_FALLBACK);
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
+ goto out;
+ }
+ VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
folio_put(folio);
count_vm_event(THP_FAULT_FALLBACK);
count_vm_event(THP_FAULT_FALLBACK_CHARGE);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
- return VM_FAULT_FALLBACK;
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
+ return NULL;
}
folio_throttle_swaprate(folio, gfp);
- pgtable = pte_alloc_one(vma->vm_mm);
- if (unlikely(!pgtable)) {
- ret = VM_FAULT_OOM;
- goto release;
- }
-
- folio_zero_user(folio, vmf->address);
+ folio_zero_user(folio, addr);
/*
* The memory barrier inside __folio_mark_uptodate makes sure that
* folio_zero_user writes become visible before the set_pmd_at()
* write.
*/
__folio_mark_uptodate(folio);
+out:
+ return folio;
+}
+
+static void map_anon_folio_pmd(struct folio *folio, pmd_t *pmd,
+ struct vm_area_struct *vma, unsigned long haddr)
+{
+ pmd_t entry;
+
+ entry = mk_huge_pmd(&folio->page, vma->vm_page_prot);
+ entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+ folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
+ folio_add_lru_vma(folio, vma);
+ set_pmd_at(vma->vm_mm, haddr, pmd, entry);
+ update_mmu_cache_pmd(vma, haddr, pmd);
+ add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ count_vm_event(THP_FAULT_ALLOC);
+ count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
+ count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
+}
+
+static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf)
+{
+ unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
+ struct vm_area_struct *vma = vmf->vma;
+ struct folio *folio;
+ pgtable_t pgtable;
+ vm_fault_t ret = 0;
+
+ folio = vma_alloc_anon_folio_pmd(vma, vmf->address);
+ if (unlikely(!folio))
+ return VM_FAULT_FALLBACK;
+
+ pgtable = pte_alloc_one(vma->vm_mm);
+ if (unlikely(!pgtable)) {
+ ret = VM_FAULT_OOM;
+ goto release;
+ }
vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_none(*vmf->pmd))) {
goto unlock_release;
} else {
- pmd_t entry;
-
ret = check_stable_address_space(vma->vm_mm);
if (ret)
goto unlock_release;
@@ -1202,21 +1236,11 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
VM_BUG_ON(ret & VM_FAULT_FALLBACK);
return ret;
}
-
- entry = mk_huge_pmd(page, vma->vm_page_prot);
- entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
- folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
- folio_add_lru_vma(folio, vma);
pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
- set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
- update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
- add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ map_anon_folio_pmd(folio, vmf->pmd, vma, haddr);
mm_inc_nr_ptes(vma->vm_mm);
deferred_split_folio(folio, false);
spin_unlock(vmf->ptl);
- count_vm_event(THP_FAULT_ALLOC);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
- count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
}
return 0;
@@ -1283,8 +1307,6 @@ static void set_huge_zero_folio(pgtable_t pgtable, struct mm_struct *mm,
vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
- gfp_t gfp;
- struct folio *folio;
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
vm_fault_t ret;
@@ -1335,14 +1357,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
}
return ret;
}
- gfp = vma_thp_gfp_mask(vma);
- folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true);
- if (unlikely(!folio)) {
- count_vm_event(THP_FAULT_FALLBACK);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK);
- return VM_FAULT_FALLBACK;
- }
- return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp);
+
+ return __do_huge_pmd_anonymous_page(vmf);
}
static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
--
2.30.2
On 2024/9/24 18:16, Dev Jain wrote:
> In preparation for the second patch, abstract away the THP allocation
> logic present in the create_huge_pmd() path, which corresponds to the
> faulting case when no page is present.
>
> There should be no functional change as a result of applying this patch,
> except that, as David notes at [1], a PMD-aligned address should
> be passed to update_mmu_cache_pmd().
>
> [1]: https://lore.kernel.org/all/ddd3fcd2-48b3-4170-bcaa-2fe66e093f43@redhat.com/
>
> Acked-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Dev Jain <dev.jain@arm.com>
> ---
> mm/huge_memory.c | 98 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 57 insertions(+), 41 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 4e34b7f89daf..bdbf67c18f6c 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1148,47 +1148,81 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
> }
> EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
>
> -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
> - struct page *page, gfp_t gfp)
> +static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
> + unsigned long addr)
> {
> - struct vm_area_struct *vma = vmf->vma;
> - struct folio *folio = page_folio(page);
> - pgtable_t pgtable;
> - unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> - vm_fault_t ret = 0;
> + unsigned long haddr = addr & HPAGE_PMD_MASK;
> + gfp_t gfp = vma_thp_gfp_mask(vma);
> + const int order = HPAGE_PMD_ORDER;
> + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true);
There is a warning without NUMA,
../mm/huge_memory.c: In function ‘vma_alloc_anon_folio_pmd’:
../mm/huge_memory.c:1154:16: warning: unused variable ‘haddr’
[-Wunused-variable]
1154 | unsigned long haddr = addr & HPAGE_PMD_MASK;
| ^~~~~
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c584e77efe10..147a6e069c71 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1151,11 +1151,11 @@ EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
unsigned long addr)
{
- unsigned long haddr = addr & HPAGE_PMD_MASK;
gfp_t gfp = vma_thp_gfp_mask(vma);
const int order = HPAGE_PMD_ORDER;
- struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true);
+ struct folio *folio;
+ folio = vma_alloc_folio(gfp, order, vma, addr & HPAGE_PMD_MASK,
true);
if (unlikely(!folio)) {
count_vm_event(THP_FAULT_FALLBACK);
count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
>
> - VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
> + if (unlikely(!folio)) {
> + count_vm_event(THP_FAULT_FALLBACK);
> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
> + goto out;
Maybe return NULL to omit the out?
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> + }
>
> + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
> if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
> folio_put(folio);
> count_vm_event(THP_FAULT_FALLBACK);
> count_vm_event(THP_FAULT_FALLBACK_CHARGE);
> - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK);
> - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
> - return VM_FAULT_FALLBACK;
> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
> + return NULL;
> }
> folio_throttle_swaprate(folio, gfp);
>
> - pgtable = pte_alloc_one(vma->vm_mm);
> - if (unlikely(!pgtable)) {
> - ret = VM_FAULT_OOM;
> - goto release;
> - }
> -
> - folio_zero_user(folio, vmf->address);
> + folio_zero_user(folio, addr);
> /*
> * The memory barrier inside __folio_mark_uptodate makes sure that
> * folio_zero_user writes become visible before the set_pmd_at()
> * write.
> */
> __folio_mark_uptodate(folio);
> +out:
> + return folio;
> +}
> +
> +static void map_anon_folio_pmd(struct folio *folio, pmd_t *pmd,
> + struct vm_area_struct *vma, unsigned long haddr)
> +{
> + pmd_t entry;
> +
> + entry = mk_huge_pmd(&folio->page, vma->vm_page_prot);
> + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
> + folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
> + folio_add_lru_vma(folio, vma);
> + set_pmd_at(vma->vm_mm, haddr, pmd, entry);
> + update_mmu_cache_pmd(vma, haddr, pmd);
> + add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
> + count_vm_event(THP_FAULT_ALLOC);
> + count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
> + count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
> +}
> +
> +static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf)
> +{
> + unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> + struct vm_area_struct *vma = vmf->vma;
> + struct folio *folio;
> + pgtable_t pgtable;
> + vm_fault_t ret = 0;
> +
> + folio = vma_alloc_anon_folio_pmd(vma, vmf->address);
> + if (unlikely(!folio))
> + return VM_FAULT_FALLBACK;
> +
> + pgtable = pte_alloc_one(vma->vm_mm);
> + if (unlikely(!pgtable)) {
> + ret = VM_FAULT_OOM;
> + goto release;
> + }
>
> vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
> if (unlikely(!pmd_none(*vmf->pmd))) {
> goto unlock_release;
> } else {
> - pmd_t entry;
> -
> ret = check_stable_address_space(vma->vm_mm);
> if (ret)
> goto unlock_release;
> @@ -1202,21 +1236,11 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
> VM_BUG_ON(ret & VM_FAULT_FALLBACK);
> return ret;
> }
> -
> - entry = mk_huge_pmd(page, vma->vm_page_prot);
> - entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
> - folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
> - folio_add_lru_vma(folio, vma);
> pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
> - set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
> - update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
> - add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
> + map_anon_folio_pmd(folio, vmf->pmd, vma, haddr);
> mm_inc_nr_ptes(vma->vm_mm);
> deferred_split_folio(folio, false);
> spin_unlock(vmf->ptl);
> - count_vm_event(THP_FAULT_ALLOC);
> - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
> - count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
> }
>
> return 0;
> @@ -1283,8 +1307,6 @@ static void set_huge_zero_folio(pgtable_t pgtable, struct mm_struct *mm,
> vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
> {
> struct vm_area_struct *vma = vmf->vma;
> - gfp_t gfp;
> - struct folio *folio;
> unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> vm_fault_t ret;
>
> @@ -1335,14 +1357,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
> }
> return ret;
> }
> - gfp = vma_thp_gfp_mask(vma);
> - folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true);
> - if (unlikely(!folio)) {
> - count_vm_event(THP_FAULT_FALLBACK);
> - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK);
> - return VM_FAULT_FALLBACK;
> - }
> - return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp);
> +
> + return __do_huge_pmd_anonymous_page(vmf);
> }
>
> static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
On 9/24/24 16:50, Kefeng Wang wrote:
>
>
> On 2024/9/24 18:16, Dev Jain wrote:
>> In preparation for the second patch, abstract away the THP allocation
>> logic present in the create_huge_pmd() path, which corresponds to the
>> faulting case when no page is present.
>>
>> There should be no functional change as a result of applying this patch,
>> except that, as David notes at [1], a PMD-aligned address should
>> be passed to update_mmu_cache_pmd().
>>
>> [1]:
>> https://lore.kernel.org/all/ddd3fcd2-48b3-4170-bcaa-2fe66e093f43@redhat.com/
>>
>> Acked-by: David Hildenbrand <david@redhat.com>
>> Signed-off-by: Dev Jain <dev.jain@arm.com>
>> ---
>> mm/huge_memory.c | 98 ++++++++++++++++++++++++++++--------------------
>> 1 file changed, 57 insertions(+), 41 deletions(-)
>>
>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>> index 4e34b7f89daf..bdbf67c18f6c 100644
>> --- a/mm/huge_memory.c
>> +++ b/mm/huge_memory.c
>> @@ -1148,47 +1148,81 @@ unsigned long thp_get_unmapped_area(struct
>> file *filp, unsigned long addr,
>> }
>> EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
>> -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
>> - struct page *page, gfp_t gfp)
>> +static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct
>> *vma,
>> + unsigned long addr)
>> {
>> - struct vm_area_struct *vma = vmf->vma;
>> - struct folio *folio = page_folio(page);
>> - pgtable_t pgtable;
>> - unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>> - vm_fault_t ret = 0;
>> + unsigned long haddr = addr & HPAGE_PMD_MASK;
>> + gfp_t gfp = vma_thp_gfp_mask(vma);
>> + const int order = HPAGE_PMD_ORDER;
>> + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr,
>> true);
>
> There is a warning without NUMA,
>
> ../mm/huge_memory.c: In function ‘vma_alloc_anon_folio_pmd’:
> ../mm/huge_memory.c:1154:16: warning: unused variable ‘haddr’
> [-Wunused-variable]
> 1154 | unsigned long haddr = addr & HPAGE_PMD_MASK;
> | ^~~~~
>
But why is this happening?
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index c584e77efe10..147a6e069c71 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1151,11 +1151,11 @@ EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
> static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct
> *vma,
> unsigned long addr)
> {
> - unsigned long haddr = addr & HPAGE_PMD_MASK;
> gfp_t gfp = vma_thp_gfp_mask(vma);
> const int order = HPAGE_PMD_ORDER;
> - struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr,
> true);
> + struct folio *folio;
>
> + folio = vma_alloc_folio(gfp, order, vma, addr &
> HPAGE_PMD_MASK, true);
> if (unlikely(!folio)) {
> count_vm_event(THP_FAULT_FALLBACK);
> count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
>
>> - VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
>> + if (unlikely(!folio)) {
>> + count_vm_event(THP_FAULT_FALLBACK);
>> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
>> + goto out;
>
> Maybe return NULL to omit the out?
Ah sorry, I have made a mess of unnecessary delayed returns :)
>
>
> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Thanks!
>
>
>> + }
>> + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
>> if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
>> folio_put(folio);
>> count_vm_event(THP_FAULT_FALLBACK);
>> count_vm_event(THP_FAULT_FALLBACK_CHARGE);
>> - count_mthp_stat(HPAGE_PMD_ORDER,
>> MTHP_STAT_ANON_FAULT_FALLBACK);
>> - count_mthp_stat(HPAGE_PMD_ORDER,
>> MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
>> - return VM_FAULT_FALLBACK;
>> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
>> + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
>> + return NULL;
>> }
>> folio_throttle_swaprate(folio, gfp);
>> - pgtable = pte_alloc_one(vma->vm_mm);
>> - if (unlikely(!pgtable)) {
>> - ret = VM_FAULT_OOM;
>> - goto release;
>> - }
>> -
>> - folio_zero_user(folio, vmf->address);
>> + folio_zero_user(folio, addr);
>> /*
>> * The memory barrier inside __folio_mark_uptodate makes sure that
>> * folio_zero_user writes become visible before the set_pmd_at()
>> * write.
>> */
>> __folio_mark_uptodate(folio);
>> +out:
>> + return folio;
>> +}
>> +
>> +static void map_anon_folio_pmd(struct folio *folio, pmd_t *pmd,
>> + struct vm_area_struct *vma, unsigned long haddr)
>> +{
>> + pmd_t entry;
>> +
>> + entry = mk_huge_pmd(&folio->page, vma->vm_page_prot);
>> + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
>> + folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
>> + folio_add_lru_vma(folio, vma);
>> + set_pmd_at(vma->vm_mm, haddr, pmd, entry);
>> + update_mmu_cache_pmd(vma, haddr, pmd);
>> + add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
>> + count_vm_event(THP_FAULT_ALLOC);
>> + count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
>> + count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
>> +}
>> +
>> +static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf)
>> +{
>> + unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>> + struct vm_area_struct *vma = vmf->vma;
>> + struct folio *folio;
>> + pgtable_t pgtable;
>> + vm_fault_t ret = 0;
>> +
>> + folio = vma_alloc_anon_folio_pmd(vma, vmf->address);
>> + if (unlikely(!folio))
>> + return VM_FAULT_FALLBACK;
>> +
>> + pgtable = pte_alloc_one(vma->vm_mm);
>> + if (unlikely(!pgtable)) {
>> + ret = VM_FAULT_OOM;
>> + goto release;
>> + }
>> vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
>> if (unlikely(!pmd_none(*vmf->pmd))) {
>> goto unlock_release;
>> } else {
>> - pmd_t entry;
>> -
>> ret = check_stable_address_space(vma->vm_mm);
>> if (ret)
>> goto unlock_release;
>> @@ -1202,21 +1236,11 @@ static vm_fault_t
>> __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
>> VM_BUG_ON(ret & VM_FAULT_FALLBACK);
>> return ret;
>> }
>> -
>> - entry = mk_huge_pmd(page, vma->vm_page_prot);
>> - entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
>> - folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
>> - folio_add_lru_vma(folio, vma);
>> pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
>> - set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
>> - update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
>> - add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
>> + map_anon_folio_pmd(folio, vmf->pmd, vma, haddr);
>> mm_inc_nr_ptes(vma->vm_mm);
>> deferred_split_folio(folio, false);
>> spin_unlock(vmf->ptl);
>> - count_vm_event(THP_FAULT_ALLOC);
>> - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC);
>> - count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
>> }
>> return 0;
>> @@ -1283,8 +1307,6 @@ static void set_huge_zero_folio(pgtable_t
>> pgtable, struct mm_struct *mm,
>> vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
>> {
>> struct vm_area_struct *vma = vmf->vma;
>> - gfp_t gfp;
>> - struct folio *folio;
>> unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>> vm_fault_t ret;
>> @@ -1335,14 +1357,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct
>> vm_fault *vmf)
>> }
>> return ret;
>> }
>> - gfp = vma_thp_gfp_mask(vma);
>> - folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true);
>> - if (unlikely(!folio)) {
>> - count_vm_event(THP_FAULT_FALLBACK);
>> - count_mthp_stat(HPAGE_PMD_ORDER,
>> MTHP_STAT_ANON_FAULT_FALLBACK);
>> - return VM_FAULT_FALLBACK;
>> - }
>> - return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp);
>> +
>> + return __do_huge_pmd_anonymous_page(vmf);
>> }
>> static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned
>> long addr,
>
On 2024/9/24 20:17, Dev Jain wrote:
>
> On 9/24/24 16:50, Kefeng Wang wrote:
>>
>>
>> On 2024/9/24 18:16, Dev Jain wrote:
>>> In preparation for the second patch, abstract away the THP allocation
>>> logic present in the create_huge_pmd() path, which corresponds to the
>>> faulting case when no page is present.
>>>
>>> There should be no functional change as a result of applying this patch,
>>> except that, as David notes at [1], a PMD-aligned address should
>>> be passed to update_mmu_cache_pmd().
>>>
>>> [1]: https://lore.kernel.org/all/ddd3fcd2-48b3-4170-
>>> bcaa-2fe66e093f43@redhat.com/
>>>
>>> Acked-by: David Hildenbrand <david@redhat.com>
>>> Signed-off-by: Dev Jain <dev.jain@arm.com>
>>> ---
>>> mm/huge_memory.c | 98 ++++++++++++++++++++++++++++--------------------
>>> 1 file changed, 57 insertions(+), 41 deletions(-)
>>>
>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>>> index 4e34b7f89daf..bdbf67c18f6c 100644
>>> --- a/mm/huge_memory.c
>>> +++ b/mm/huge_memory.c
>>> @@ -1148,47 +1148,81 @@ unsigned long thp_get_unmapped_area(struct
>>> file *filp, unsigned long addr,
>>> }
>>> EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
>>> -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
>>> - struct page *page, gfp_t gfp)
>>> +static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct
>>> *vma,
>>> + unsigned long addr)
>>> {
>>> - struct vm_area_struct *vma = vmf->vma;
>>> - struct folio *folio = page_folio(page);
>>> - pgtable_t pgtable;
>>> - unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>>> - vm_fault_t ret = 0;
>>> + unsigned long haddr = addr & HPAGE_PMD_MASK;
>>> + gfp_t gfp = vma_thp_gfp_mask(vma);
>>> + const int order = HPAGE_PMD_ORDER;
>>> + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr,
>>> true);
>>
>> There is a warning without NUMA,
>>
>> ../mm/huge_memory.c: In function ‘vma_alloc_anon_folio_pmd’:
>> ../mm/huge_memory.c:1154:16: warning: unused variable ‘haddr’ [-
>> Wunused-variable]
>> 1154 | unsigned long haddr = addr & HPAGE_PMD_MASK;
>> | ^~~~~
>>
>
> But why is this happening?
If no CONFIG_NUMA, vma_alloc_folio(...) = folio_alloc_noprof(gfp, order),
it won't use haddr.
On 9/24/24 18:24, Kefeng Wang wrote:
>
>
> On 2024/9/24 20:17, Dev Jain wrote:
>>
>> On 9/24/24 16:50, Kefeng Wang wrote:
>>>
>>>
>>> On 2024/9/24 18:16, Dev Jain wrote:
>>>> In preparation for the second patch, abstract away the THP allocation
>>>> logic present in the create_huge_pmd() path, which corresponds to the
>>>> faulting case when no page is present.
>>>>
>>>> There should be no functional change as a result of applying this
>>>> patch,
>>>> except that, as David notes at [1], a PMD-aligned address should
>>>> be passed to update_mmu_cache_pmd().
>>>>
>>>> [1]: https://lore.kernel.org/all/ddd3fcd2-48b3-4170-
>>>> bcaa-2fe66e093f43@redhat.com/
>>>>
>>>> Acked-by: David Hildenbrand <david@redhat.com>
>>>> Signed-off-by: Dev Jain <dev.jain@arm.com>
>>>> ---
>>>> mm/huge_memory.c | 98
>>>> ++++++++++++++++++++++++++++--------------------
>>>> 1 file changed, 57 insertions(+), 41 deletions(-)
>>>>
>>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>>>> index 4e34b7f89daf..bdbf67c18f6c 100644
>>>> --- a/mm/huge_memory.c
>>>> +++ b/mm/huge_memory.c
>>>> @@ -1148,47 +1148,81 @@ unsigned long thp_get_unmapped_area(struct
>>>> file *filp, unsigned long addr,
>>>> }
>>>> EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
>>>> -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault
>>>> *vmf,
>>>> - struct page *page, gfp_t gfp)
>>>> +static struct folio *vma_alloc_anon_folio_pmd(struct
>>>> vm_area_struct *vma,
>>>> + unsigned long addr)
>>>> {
>>>> - struct vm_area_struct *vma = vmf->vma;
>>>> - struct folio *folio = page_folio(page);
>>>> - pgtable_t pgtable;
>>>> - unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>>>> - vm_fault_t ret = 0;
>>>> + unsigned long haddr = addr & HPAGE_PMD_MASK;
>>>> + gfp_t gfp = vma_thp_gfp_mask(vma);
>>>> + const int order = HPAGE_PMD_ORDER;
>>>> + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr,
>>>> true);
>>>
>>> There is a warning without NUMA,
>>>
>>> ../mm/huge_memory.c: In function ‘vma_alloc_anon_folio_pmd’:
>>> ../mm/huge_memory.c:1154:16: warning: unused variable ‘haddr’ [-
>>> Wunused-variable]
>>> 1154 | unsigned long haddr = addr & HPAGE_PMD_MASK;
>>> | ^~~~~
>>>
>>
>> But why is this happening?
>
> If no CONFIG_NUMA, vma_alloc_folio(...) = folio_alloc_noprof(gfp, order),
> it won't use haddr.
Ah got it, thanks, I missed the ifdeffery in include/linux/gfp.h.
>
>
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